<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Feed_Reader
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: FeedSet.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Feed_Reader
 */
require_once 'Zend/Feed/Reader.php';

/**
 * @see Zend_Uri
 */
require_once 'Zend/Uri.php';

/**
 * @category   Zend
 * @package    Zend_Feed_Reader
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Feed_Reader_FeedSet extends ArrayObject {
	
	public $rss = null;
	
	public $rdf = null;
	
	public $atom = null;
	
	/**
	 * Import a DOMNodeList from any document containing a set of links
	 * for alternate versions of a document, which will normally refer to
	 * RSS/RDF/Atom feeds for the current document.
	 *
	 * All such links are stored internally, however the first instance of
	 * each RSS, RDF or Atom type has its URI stored as a public property
	 * as a shortcut where the use case is simply to get a quick feed ref.
	 *
	 * Note that feeds are not loaded at this point, but will be lazy
	 * loaded automatically when each links 'feed' array key is accessed.
	 *
	 * @param DOMNodeList $links
	 * @param string $uri
	 * @return void
	 */
	public function addLinks(DOMNodeList $links, $uri) {
		foreach ( $links as $link ) {
			if (strtolower ( $link->getAttribute ( 'rel' ) ) !== 'alternate' || ! $link->getAttribute ( 'type' ) || ! $link->getAttribute ( 'href' )) {
				continue;
			}
			if (! isset ( $this->rss ) && $link->getAttribute ( 'type' ) == 'application/rss+xml') {
				$this->rss = $this->_absolutiseUri ( trim ( $link->getAttribute ( 'href' ) ), $uri );
			} elseif (! isset ( $this->atom ) && $link->getAttribute ( 'type' ) == 'application/atom+xml') {
				$this->atom = $this->_absolutiseUri ( trim ( $link->getAttribute ( 'href' ) ), $uri );
			} elseif (! isset ( $this->rdf ) && $link->getAttribute ( 'type' ) == 'application/rdf+xml') {
				$this->rdf = $this->_absolutiseUri ( trim ( $link->getAttribute ( 'href' ) ), $uri );
			}
			$this [] = new self ( array ('rel' => 'alternate', 'type' => $link->getAttribute ( 'type' ), 'href' => $this->_absolutiseUri ( trim ( $link->getAttribute ( 'href' ) ), $uri ) ) );
		}
	}
	
	/**
	 * Attempt to turn a relative URI into an absolute URI
	 */
	protected function _absolutiseUri($link, $uri = null) {
		if (! Zend_Uri::check ( $link )) {
			if ($uri !== null) {
				$uri = Zend_Uri::factory ( $uri );
				
				if ($link [0] !== '/') {
					$link = $uri->getPath () . '/' . $link;
				}
				
				$link = $uri->getScheme () . '://' . $uri->getHost () . '/' . $this->_canonicalizePath ( $link );
				if (! Zend_Uri::check ( $link )) {
					$link = null;
				}
			}
		}
		return $link;
	}
	
	/**
	 * Canonicalize relative path
	 */
	protected function _canonicalizePath($path) {
		$parts = array_filter ( explode ( '/', $path ) );
		$absolutes = array ();
		foreach ( $parts as $part ) {
			if ('.' == $part) {
				continue;
			}
			if ('..' == $part) {
				array_pop ( $absolutes );
			} else {
				$absolutes [] = $part;
			}
		}
		return implode ( '/', $absolutes );
	}
	
	/**
	 * Supports lazy loading of feeds using Zend_Feed_Reader::import() but
	 * delegates any other operations to the parent class.
	 *
	 * @param string $offset
	 * @return mixed
	 * @uses Zend_Feed_Reader
	 */
	public function offsetGet($offset) {
		if ($offset == 'feed' && ! $this->offsetExists ( 'feed' )) {
			if (! $this->offsetExists ( 'href' )) {
				return null;
			}
			$feed = Zend_Feed_Reader::import ( $this->offsetGet ( 'href' ) );
			$this->offsetSet ( 'feed', $feed );
			return $feed;
		}
		return parent::offsetGet ( $offset );
	}

}
